Homeland Security Secretary John Kelly affirmed Sunday night that President Donald Trump's executive order banning refugees and travelers from several majority-Muslim countries would not apply to permanent residents, a major source of confusion in implementing the policy.

"In applying the provisions of the president's executive order, I hereby deem the entry of lawful permanent residents to be in the national interest," Kelly said in a statement. "Accordingly, absent the receipt of significant derogatory information indicating a serious threat to public safety and welfare, lawful permanent resident status will be a dispositive factor in our case-by-case determinations."

The hastily written order contained vague language and no specific guidance on whether it applied to certain groups. Permanent residents, also known as green card holders, were being admitted on a case-by-case basis.

Immigration attorneys and advocates told HuffPost that it amounted to "chaos."

"They drop this order at 4:30 p.m. on a Friday," immigration attorney David Leopold said. "Everyone's leaving the office. Lawyers are gone. Reporters are leaving for the weekend. But planes are coming into the country. Nobody had any notice whatsoever. Nobody knew this was going to apply to permanent residents."

Even Trump's chief of staff, Reince Priebus, on Sunday contradicted himself in stating whether the ban applied to permanent residents. He first told NBC's "Meet the Press" that "as far as green card holders moving forward, it doesn't affect them." But minutes later, he said, "Of course it does."

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